1. Field of the Invention
The present invention relates to a control arrangement fail-safe timing circuit, and it more particularly relates to an automatic electronic fail-safe timing circuit for controlling the activation of a system, such as a fuel ignition system or an air conditioning system.
2. Description of the Prior Art
Control arrangements for system, such as fuel ignition and air conditioning systems, have been employed to selectively activate and de-activate the systems. For example, in a fuel ignition system control arrangement, ignition circuits have been employed to establish directly a flame in main burner apparatus of the system in response to a thermostatically-controlled switch generating a starting signal for activating the ignition circuit and for turning on a valve to permit gaseous fuel under pressure to be supplied to the burner apparatus. The arrangement would attempt to ignite the main burner apparatus, and if the resulting flame were not subsequently established due to a malfunction or any other reason, unburned gas would thereby escape unnecessarily and cause fuel to be wasted. Similarly, in air conditioning system, control arrangements have been provided to initiate automatically the operation of a compressor for the system. However, if the oil pressure of the compressor does not increase to an acceptable level in a reasonable period of time, it is desirable to de-activate the compressor unit and restart it subsequently. Therefore, it would be highly desirable to have a control arrangement fail-safe timing circuit, which would prevent undesirable and unwanted conditions of the system from occurring, such conditions as the escaping of unburned gas in a wasteful manner from the main burner apparatus of a fuel ignition system and as the causing of the operation of an air conditioning compressor without sufficient oil pressure.